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Kleybolte ME, Vagin SI, Rieger B. A Polymer Lost in the Shuffle: The Perspective of Poly(para)phenylenes. MACROMOL CHEM PHYS 2023. [DOI: 10.1002/macp.202200441] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Affiliation(s)
- Moritz E. Kleybolte
- WACKER‐Chair of Macromolecular Chemistry Catalysis Research Center Technical University of Munich Lichtenbergstr. 4 85748 Garching Germany
| | - Sergei I. Vagin
- WACKER‐Chair of Macromolecular Chemistry Catalysis Research Center Technical University of Munich Lichtenbergstr. 4 85748 Garching Germany
| | - Bernhard Rieger
- WACKER‐Chair of Macromolecular Chemistry Catalysis Research Center Technical University of Munich Lichtenbergstr. 4 85748 Garching Germany
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2
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Aghajanian AH, Bigham A, Sanati A, Kefayat A, Salamat MR, Sattary M, Rafienia M. A 3D macroporous and magnetic Mg 2SiO 4-CuFe 2O 4 scaffold for bone tissue regeneration: Surface modification, in vitro and in vivo studies. BIOMATERIALS ADVANCES 2022; 137:212809. [PMID: 35929249 DOI: 10.1016/j.bioadv.2022.212809] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/28/2022] [Revised: 04/10/2022] [Accepted: 04/13/2022] [Indexed: 06/15/2023]
Abstract
Macroporous scaffolds with bioactivity and magnetic properties can be a good candidate for bone regeneration and hyperthermia. In addition, modifying the surface of the scaffolds with biocompatible materials can increase their potential for in vivo applications. Here, we developed a multifunctional nanocomposite Mg2SiO4-CuFe2O4 scaffold for bone regeneration and hyperthermia. The surface of scaffold was coated with various concentrations of poly-3-hydroxybutyrate (P3HB, 1-5% (w/v)). It was observed that 3% (w/v) of P3HB provided a favorable combination of porosity (79 ± 2.1%) and compressive strength (3.2 ± 0.11 MPa). The hyperthermia potential of samples was assessed in the presence of various magnetic fields in vitro. The coated scaffolds showed a lower degradation rate than the un-coated one up to 35 days of soaking in simulated biological medium. Due to the porous and specific morphology of P3HB, it was found that in vitro bioactivity and cell attachment were increased on the scaffold. Moreover, it was observed that the P3HB coating improved the cell viability, alkaline phosphatase activity, and mineralization of the scaffold. Finally, we studied the bone formation ability of the scaffolds in vivo, and implanted the developed scaffold in the rat's femur for 8 weeks. Micro-computed tomography results including bone volume fraction and trabecular thickness exhibited an improvement in the bone regeneration of the coated scaffold compared to the control. The overall results of this study introduce a highly macroporous scaffold with multifunctional performance, noticeable ability in bone regeneration, and hyperthermia properties for osteosarcoma.
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Affiliation(s)
- Amir Hamed Aghajanian
- Department of Biomaterials, Tissue Engineering and Nanotechnology, School of Advanced Technologies in Medicine (ATiM), Isfahan University of Medical Sciences, Isfahan, Iran
| | - Ashkan Bigham
- Institute of Polymers, Composites and Biomaterials-National Research Council (IPCB-CNR), Viale J.F. Kennedy 54-Mostra d'Oltremare pad. 20, 80125 Naples, Italy
| | - Alireza Sanati
- Biosensor Research Center, Isfahan University of Medical Sciences, Isfahan, Iran
| | - Amirhosein Kefayat
- Biosensor Research Center, Isfahan University of Medical Sciences, Isfahan, Iran; Cancer Prevention Research Center, Department of Oncology, Isfahan University of Medical Sciences, Isfahan, Iran
| | - Mohammad Reza Salamat
- Department of Medical Physics, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran
| | - Mansoureh Sattary
- Department of Biomaterials, Tissue Engineering and Nanotechnology, School of Advanced Technologies in Medicine (ATiM), Isfahan University of Medical Sciences, Isfahan, Iran
| | - Mohammad Rafienia
- Biosensor Research Center, Isfahan University of Medical Sciences, Isfahan, Iran.
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Causey GC, Picha GJ, Price J, Pelletier MH, Wang T, Walsh WR. The effect of a novel pillar surface morphology and material composition demonstrates uniform osseointegration. J Mech Behav Biomed Mater 2021; 123:104775. [PMID: 34419888 DOI: 10.1016/j.jmbbm.2021.104775] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2021] [Revised: 08/07/2021] [Accepted: 08/10/2021] [Indexed: 11/28/2022]
Abstract
Long-term survival of orthopedic implants requires a strong and compliant interface between the implant and surrounding bone. This paper further explores the in-vivo response to a novel, macro-scale osseointegration surface morphology. In this study, we examine the effects of material composition on osseointegration in relation to the controlled surface geometry. The pillared surface is constructed of discontinuous surface geometry which creates an open space for unencumbered bone migration. In creating an open, macro-scale morphology we have demonstrated a bone migration and integration that is less dependent on the underlying implant material and is substantially driven thru surface geometry. In this in-vivo study an established ovine model was used to examine the effects of implant material composition on bone ingrowth and mechanical performance. Cortical and cancellous sites in the tibia and distal femur were examined at 6 and 12 weeks with μCT, histology, histomorphometry, and mechanical performance. Implant materials tested included PEEK (Evonik, VISTAKEEP®), PEEK HA (Invibio, PEEK-OPTIMA HA Enhanced), Titanium coated PEEK, Titanium (Ti-6Al-4V, Grade 5), and Ultra-High Molecular Weight Polyethylene (UHMWPE). Extensive bone ingrowth was noted in all implant materials at 12 weeks with maturation of the bone within the pillar structure from 6 weeks to 12 weeks. Histology demonstrated little fibrous deposition at the implant interface with no adverse cellular reactions. Histomorphometric review of cortical sites revealed greater than 60% bone ingrowth at 6 weeks increasing to nearly 80% by the 12 week timepoint. Cancellous sites yielded a mean of 30% ingrowth at 6 weeks increasing to 35% by 12 weeks. Pushout testing of cortical site samples demonstrated increase in pushout force between the 6 and 12 week timepoints. Increases were significant in all but the UHMWPE samples. Stiffness likewise increased in all samples between the two times. These results demonstrated the effectiveness of the pillar morphology with full integrating from the surrounding bony tissue regardless of the material.
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Affiliation(s)
| | | | - Jamey Price
- Applied Medical Technology, Brecksville, OH, USA
| | | | - Tian Wang
- The University of New South Wales, Australia
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Mohd Roslan MR, Mohd Kamal NL, Abdul Khalid MF, Mohd Nasir NF, Cheng EM, Beh CY, Tan JS, Mohamed MS. The State of Starch/Hydroxyapatite Composite Scaffold in Bone Tissue Engineering with Consideration for Dielectric Measurement as an Alternative Characterization Technique. MATERIALS 2021; 14:ma14081960. [PMID: 33919814 PMCID: PMC8070798 DOI: 10.3390/ma14081960] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/06/2021] [Revised: 03/21/2021] [Accepted: 03/27/2021] [Indexed: 01/06/2023]
Abstract
Hydroxyapatite (HA) has been widely used as a scaffold in tissue engineering. HA possesses high mechanical stress and exhibits particularly excellent biocompatibility owing to its similarity to natural bone. Nonetheless, this ceramic scaffold has limited applications due to its apparent brittleness. Therefore, this had presented some difficulties when shaping implants out of HA and for sustaining a high mechanical load. Fortunately, these drawbacks can be improved by combining HA with other biomaterials. Starch was heavily considered for biomedical device applications in favor of its low cost, wide availability, and biocompatibility properties that complement HA. This review provides an insight into starch/HA composites used in the fabrication of bone tissue scaffolds and numerous factors that influence the scaffold properties. Moreover, an alternative characterization of scaffolds via dielectric and free space measurement as a potential contactless and nondestructive measurement method is also highlighted.
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Affiliation(s)
- Mohd Riza Mohd Roslan
- Biomedical Electronic Engineering Program, School of Mechatronic Engineering, Universiti Malaysia Perlis, Arau 02600, Perlis, Malaysia; (M.R.M.R.); (N.F.M.N.); (E.M.C.); (C.Y.B.)
| | - Nadhiya Liyana Mohd Kamal
- Malaysian Institute of Aviation Technology, Universiti Kuala Lumpur, Dengkil 43800, Selangor, Malaysia;
| | - Muhammad Farid Abdul Khalid
- Faculty of Electrical Engineering, Microwave Research Institute (MRI), Universiti Teknologi MARA (UiTM), Shah Alam 40450, Selangor, Malaysia;
| | - Nashrul Fazli Mohd Nasir
- Biomedical Electronic Engineering Program, School of Mechatronic Engineering, Universiti Malaysia Perlis, Arau 02600, Perlis, Malaysia; (M.R.M.R.); (N.F.M.N.); (E.M.C.); (C.Y.B.)
- Sports Engineering Research Centre (SERC), Universiti Malaysia Perlis, Arau 02600, Perlis, Malaysia
| | - Ee Meng Cheng
- Biomedical Electronic Engineering Program, School of Mechatronic Engineering, Universiti Malaysia Perlis, Arau 02600, Perlis, Malaysia; (M.R.M.R.); (N.F.M.N.); (E.M.C.); (C.Y.B.)
| | - Chong You Beh
- Biomedical Electronic Engineering Program, School of Mechatronic Engineering, Universiti Malaysia Perlis, Arau 02600, Perlis, Malaysia; (M.R.M.R.); (N.F.M.N.); (E.M.C.); (C.Y.B.)
| | - Joo Shun Tan
- Bioprocess Technology, School of Industrial Technology, Universiti Sains Malaysia, Gelugor 11800, Pulau Pinang, Malaysia;
- Bioprocessing and Biomanufacturing Research Centre, Universiti Putra Malaysia (UPM), Serdang 43400, Selangor, Malaysia
| | - Mohd Shamzi Mohamed
- Bioprocessing and Biomanufacturing Research Centre, Universiti Putra Malaysia (UPM), Serdang 43400, Selangor, Malaysia
- Department of Bioprocess Technology, Universiti Putra Malaysia (UPM), Serdang 43400, Selangor, Malaysia
- Correspondence:
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Liquid Crystal Elastomers for Biological Applications. NANOMATERIALS 2021; 11:nano11030813. [PMID: 33810173 PMCID: PMC8005174 DOI: 10.3390/nano11030813] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/14/2021] [Revised: 03/17/2021] [Accepted: 03/18/2021] [Indexed: 11/16/2022]
Abstract
The term liquid crystal elastomer (LCE) describes a class of materials that combine the elastic entropy behaviour associated with conventional elastomers with the stimuli responsive properties of anisotropic liquid crystals. LCEs consequently exhibit attributes of both elastomers and liquid crystals, but additionally have unique properties not found in either. Recent developments in LCE synthesis, as well as the understanding of the behaviour of liquid crystal elastomers—namely their mechanical, optical and responsive properties—is of significant relevance to biology and biomedicine. LCEs are abundant in nature, highlighting the potential use of LCEs in biomimetics. Their exceptional tensile properties and biocompatibility have led to research exploring their applications in artificial tissue, biological sensors and cell scaffolds by exploiting their actuation and shock absorption properties. There has also been significant recent interest in using LCEs as a model for morphogenesis. This review provides an overview of some aspects of LCEs which are of relevance in different branches of biology and biomedicine, as well as discussing how recent LCE advances could impact future applications.
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Moldero IL, Chandra A, Cavo M, Mota C, Kapsokalyvas D, Gigli G, Moroni L, Del Mercato LL. Probing the pH Microenvironment of Mesenchymal Stromal Cell Cultures on Additive-Manufactured Scaffolds. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2020; 16:e2002258. [PMID: 32656904 DOI: 10.1002/smll.202002258] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/07/2020] [Revised: 06/05/2020] [Indexed: 05/22/2023]
Abstract
Despite numerous advances in the field of tissue engineering and regenerative medicine, monitoring the formation of tissue regeneration and its metabolic variations during culture is still a challenge and mostly limited to bulk volumetric assays. Here, a simple method of adding capsules-based optical sensors in cell-seeded 3D scaffolds is presented and the potential of these sensors to monitor the pH changes in space and time during cell growth is demonstrated. It is shown that the pH decreased over time in the 3D scaffolds, with a more prominent decrease at the edges of the scaffolds. Moreover, the pH change is higher in 3D scaffolds compared to monolayered 2D cell cultures. The results suggest that this system, composed by capsules-based optical sensors and 3D scaffolds with predefined geometry and pore architecture network, can be a suitable platform for monitoring pH variations during 3D cell growth and tissue formation. This is particularly relevant for the investigation of 3D cellular microenvironment alterations occurring both during physiological processes, such as tissue regeneration, and pathological processes, such as cancer evolution.
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Affiliation(s)
- Ivan Lorenzo Moldero
- Department of Complex Tissue Regeneration, MERLN Institute for Technology-Inspired Regenerative Medicine, Maastricht University, Maastricht, 6229ER, The Netherlands
| | - Anil Chandra
- Institute of Nanotechnology, National Research Council (CNR-NANOTEC), Campus Ecotekne, via Monteroni, Lecce, 73100, Italy
| | - Marta Cavo
- Institute of Nanotechnology, National Research Council (CNR-NANOTEC), Campus Ecotekne, via Monteroni, Lecce, 73100, Italy
| | - Carlos Mota
- Department of Complex Tissue Regeneration, MERLN Institute for Technology-Inspired Regenerative Medicine, Maastricht University, Maastricht, 6229ER, The Netherlands
| | - Dimitrios Kapsokalyvas
- Department of Molecular Cell Biology, Maastricht University Medical Center, UNS 50, Maastricht, 6229ER, The Netherlands
| | - Giuseppe Gigli
- Institute of Nanotechnology, National Research Council (CNR-NANOTEC), Campus Ecotekne, via Monteroni, Lecce, 73100, Italy
- Department of Mathematics and Physics "Ennio De Giorgi", University of Salento, via Arnesano, Lecce, 73100, Italy
| | - Lorenzo Moroni
- Department of Complex Tissue Regeneration, MERLN Institute for Technology-Inspired Regenerative Medicine, Maastricht University, Maastricht, 6229ER, The Netherlands
- Institute of Nanotechnology, National Research Council (CNR-NANOTEC), Campus Ecotekne, via Monteroni, Lecce, 73100, Italy
| | - Loretta L Del Mercato
- Institute of Nanotechnology, National Research Council (CNR-NANOTEC), Campus Ecotekne, via Monteroni, Lecce, 73100, Italy
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Ahn H, Patel RR, Hoyt AJ, Lin ASP, Torstrick FB, Guldberg RE, Frick CP, Carpenter RD, Yakacki CM, Willett NJ. Biological evaluation and finite-element modeling of porous poly(para-phenylene) for orthopaedic implants. Acta Biomater 2018; 72:352-361. [PMID: 29563069 DOI: 10.1016/j.actbio.2018.03.025] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2017] [Revised: 03/08/2018] [Accepted: 03/13/2018] [Indexed: 12/22/2022]
Abstract
Poly(para-phenylene) (PPP) is a novel aromatic polymer with higher strength and stiffness than polyetheretherketone (PEEK), the gold standard material for polymeric load-bearing orthopaedic implants. The amorphous structure of PPP makes it relatively straightforward to manufacture different architectures, while maintaining mechanical properties. PPP is promising as a potential orthopaedic material; however, the biocompatibility and osseointegration have not been well investigated. The objective of this study was to evaluate biological and mechanical behavior of PPP, with or without porosity, in comparison to PEEK. We examined four specific constructs: 1) solid PPP, 2) solid PEEK, 3) porous PPP and 4) porous PEEK. Pre-osteoblasts (MC3T3) exhibited similar cell proliferation among the materials. Osteogenic potential was significantly increased in the porous PPP scaffold as assessed by ALP activity and calcium mineralization. In vivo osseointegration was assessed by implanting the cylindrical materials into a defect in the metaphysis region of rat tibiae. Significantly more mineral ingrowth was observed in both porous scaffolds compared to the solid scaffolds, and porous PPP had a further increase compared to porous PEEK. Additionally, porous PPP implants showed bone formation throughout the porous structure when observed via histology. A computational simulation of mechanical push-out strength showed approximately 50% higher interfacial strength in the porous PPP implants compared to the porous PEEK implants and similar stress dissipation. These data demonstrate the potential utility of PPP for orthopaedic applications and show improved osseointegration when compared to the currently available polymeric material. STATEMENT OF SIGNIFICANCE PEEK has been widely used in orthopaedic surgery; however, the ability to utilize PEEK for advanced fabrication methods, such as 3D printing and tailored porosity, remain challenging. We present a promising new orthopaedic biomaterial, Poly(para-phenylene) (PPP), which is a novel class of aromatic polymers with higher strength and stiffness than polyetheretherketone (PEEK). PPP has exceptional mechanical strength and stiffness due to its repeating aromatic rings that provide strong anti-rotational biaryl bonds. Furthermore, PPP has an amorphous structure making it relatively easier to manufacture (via molding or solvent-casting techniques) into different geometries with and without porosity. This ability to manufacture different architectures and use different processes while maintaining mechanical properties makes PPP a very promising potential orthopaedic biomaterial which may allow for closer matching of mechanical properties between the host bone tissue while also allowing for enhanced osseointegration. In this manuscript, we look at the potential of porous and solid PPP in comparison to PEEK. We measured the mechanical properties of PPP and PEEK scaffolds, tested these scaffolds in vitro for osteocompatibility with MC3T3 cells, and then tested the osseointegration and subsequent functional integration in vivo in a metaphyseal drill hole model in rat tibia. We found that PPP permits cell adhesion, growth, and mineralization in vitro. In vivo it was found that porous PPP significantly enhanced mineralization into the construct and increased the mechanical strength required to push out the scaffold in comparison to PEEK. This is the first study to investigate the performance of PPP as an orthopaedic biomaterial in vivo. PPP is an attractive material for orthopaedic implants due to the ease of manufacturing and superior mechanical strength.
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Affiliation(s)
- Hyunhee Ahn
- Department of Orthopaedics, Emory University, Atlanta, GA, USA; The Atlanta Veterans Affairs Medical Center Atlanta, Decatur, GA, USA
| | - Ravi R Patel
- Department of Mechanical Engineering, University of Colorado, Denver, CO, USA
| | - Anthony J Hoyt
- Department of Mechanical Engineering, University of Wyoming, Laramie, WY, USA
| | - Angela S P Lin
- George W. Woodruff School of Mechanical Engineering, Petit Institute for Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, GA, USA
| | - F Brennan Torstrick
- George W. Woodruff School of Mechanical Engineering, Petit Institute for Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, GA, USA
| | - Robert E Guldberg
- George W. Woodruff School of Mechanical Engineering, Petit Institute for Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, GA, USA
| | - Carl P Frick
- Department of Mechanical Engineering, University of Wyoming, Laramie, WY, USA
| | - R Dana Carpenter
- Department of Mechanical Engineering, University of Colorado, Denver, CO, USA
| | | | - Nick J Willett
- Department of Orthopaedics, Emory University, Atlanta, GA, USA; The Atlanta Veterans Affairs Medical Center Atlanta, Decatur, GA, USA.
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Prévôt ME, Ustunel S, Hegmann E. Liquid Crystal Elastomers-A Path to Biocompatible and Biodegradable 3D-LCE Scaffolds for Tissue Regeneration. MATERIALS (BASEL, SWITZERLAND) 2018; 11:E377. [PMID: 29510523 PMCID: PMC5872956 DOI: 10.3390/ma11030377] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/02/2018] [Revised: 02/21/2018] [Accepted: 02/23/2018] [Indexed: 11/25/2022]
Abstract
The development of appropriate materials that can make breakthroughs in tissue engineering has long been pursued by the scientific community. Several types of material have been long tested and re-designed for this purpose. At the same time, liquid crystals (LCs) have captivated the scientific community since their discovery in 1888 and soon after were thought to be, in combination with polymers, artificial muscles. Within the past decade liquid crystal elastomers (LCE) have been attracting increasing interest for their use as smart advanced materials for biological applications. Here, we examine how LCEs can potentially be used as dynamic substrates for culturing cells, moving away from the classical two-dimensional cell-culture nature. We also briefly discuss the integration of a few technologies for the preparation of more sophisticated LCE-composite scaffolds for more dynamic biomaterials. The anisotropic properties of LCEs can be used not only to promote cell attachment and the proliferation of cells, but also to promote cell alignment under LCE-stimulated deformation. 3D LCEs are ideal materials for new insights to simulate and study the development of tissues and the complex interplay between cells.
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Affiliation(s)
- Marianne E Prévôt
- Liquid Crystal Institute, Kent State University, Kent, OH 44242, USA.
| | - Senay Ustunel
- Liquid Crystal Institute, Kent State University, Kent, OH 44242, USA.
- Chemical Physics Interdisciplinary Program (CPIP), Kent State University, Kent, OH 44242, USA.
| | - Elda Hegmann
- Liquid Crystal Institute, Kent State University, Kent, OH 44242, USA.
- Chemical Physics Interdisciplinary Program (CPIP), Kent State University, Kent, OH 44242, USA.
- Department of Biological Sciences, Kent State University, Kent, OH 44242, USA.
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Chatham LS, Patel VV, Yakacki CM, Dana Carpenter R. Interbody Spacer Material Properties and Design Conformity for Reducing Subsidence During Lumbar Interbody Fusion. J Biomech Eng 2017; 139:2613838. [PMID: 28334320 DOI: 10.1115/1.4036312] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2016] [Indexed: 11/08/2022]
Abstract
There is a need to better understand the effects of intervertebral spacer material and design on the stress distribution in vertebral bodies and endplates to help reduce complications such as subsidence and improve outcomes following lumbar interbody fusion. The main objective of this study was to investigate the effects of spacer material on the stress and strain in the lumbar spine after interbody fusion with posterior instrumentation. A standard spacer was also compared with a custom-fit spacer, which conformed to the vertebral endplates, to determine if a custom fit would reduce stress on the endplates. A finite element (FE) model of the L4-L5 motion segment was developed from computed tomography (CT) images of a cadaveric lumbar spine. An interbody spacer, pedicle screws, and posterior rods were incorporated into the image-based model. The model was loaded in axial compression, and strain and stress were determined in the vertebra, spacer, and rods. Polyetheretherketone (PEEK), titanium, poly(para-phenylene) (PPP), and porous PPP (70% by volume) were used as the spacer material to quantify the effects on stress and strain in the system. Experimental testing of a cadaveric specimen was used to validate the model's results. There were no large differences in stress levels (<3%) at the bone-spacer interfaces and the rods when PEEK was used instead of titanium. Use of the porous PPP spacer produced an 8-15% decrease of stress at the bone-spacer interfaces and posterior rods. The custom-shaped spacer significantly decreased (>37%) the stress at the bone-spacer interfaces for all materials tested. A 28% decrease in stress was found in the posterior rods with the custom spacer. Of all the spacer materials tested with the custom spacer design, 70% porous PPP resulted in the lowest stress at the bone-spacer interfaces. The results show the potential for more compliant materials to reduce stress on the vertebral endplates postsurgery. The custom spacer provided a greater contact area between the spacer and bone, which distributed the stress more evenly, highlighting a possible strategy to decrease the risk of subsidence.
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Affiliation(s)
- Lillian S Chatham
- Department of Mechanical Engineering, University of Colorado Denver, Denver, CO 80204
| | - Vikas V Patel
- Department of Orthopaedic Surgery, University of Colorado Denver, Anschutz Medical Campus, Aurora, CO 80045
| | - Christopher M Yakacki
- Department of Mechanical Engineering, University of Colorado Denver, Denver, CO 80204
| | - R Dana Carpenter
- Department of Mechanical Engineering, University of Colorado Denver, Denver, CO 80204
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Evans NT, Torstrick FB, Safranski DL, Guldberg RE, Gall K. Local deformation behavior of surface porous polyether-ether-ketone. J Mech Behav Biomed Mater 2017; 65:522-532. [DOI: 10.1016/j.jmbbm.2016.09.006] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2016] [Revised: 09/02/2016] [Accepted: 09/04/2016] [Indexed: 10/21/2022]
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Evans NT, Torstrick FB, Lee CSD, Dupont KM, Safranski DL, Chang WA, Macedo AE, Lin ASP, Boothby JM, Whittingslow DC, Carson RA, Guldberg RE, Gall K. High-strength, surface-porous polyether-ether-ketone for load-bearing orthopedic implants. Acta Biomater 2015; 13:159-67. [PMID: 25463499 DOI: 10.1016/j.actbio.2014.11.030] [Citation(s) in RCA: 103] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2014] [Revised: 09/26/2014] [Accepted: 11/17/2014] [Indexed: 12/19/2022]
Abstract
Despite its widespread clinical use in load-bearing orthopedic implants, polyether-ether-ketone (PEEK) is often associated with poor osseointegration. In this study, a surface-porous PEEK material (PEEK-SP) was created using a melt extrusion technique. The porous layer was 399.6±63.3 μm thick and possessed a mean pore size of 279.9±31.6 μm, strut spacing of 186.8±55.5 μm, porosity of 67.3±3.1% and interconnectivity of 99.9±0.1%. Monotonic tensile tests showed that PEEK-SP preserved 73.9% of the strength (71.06±2.17 MPa) and 73.4% of the elastic modulus (2.45±0.31 GPa) of as-received, injection-molded PEEK. PEEK-SP further demonstrated a fatigue strength of 60.0 MPa at one million cycles, preserving 73.4% of the fatigue resistance of injection-molded PEEK. Interfacial shear testing showed the pore layer shear strength to be 23.96±2.26 MPa. An osseointegration model in the rat revealed substantial bone formation within the pore layer at 6 and 12 weeks via microcomputed tomography and histological evaluation. Ingrown bone was more closely apposed to the pore wall and fibrous tissue growth was reduced in PEEK-SP when compared to non-porous PEEK controls. These results indicate that PEEK-SP could provide improved osseointegration while maintaining the structural integrity necessary for load-bearing orthopedic applications.
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Affiliation(s)
- Nathan T Evans
- School of Materials Science and Engineering, 771 Ferst Drive, J. Erskine Love Building, Georgia Institute of Technology, Atlanta, GA 30332, USA.
| | - F Brennan Torstrick
- George W. Woodruff School of Mechanical Engineering, 801 Ferst Drive, Georgia Institute of Technology, Atlanta, GA 30332, USA; Parker H. Petit Institute for Bioengineering and Bioscience, 315 Ferst Drive, Georgia Institute of Technology, Atlanta, GA 30332, USA
| | | | - Kenneth M Dupont
- MedShape, Inc., 1575 Northside Drive, NW, Suite 440, Atlanta, GA 30318, USA
| | - David L Safranski
- MedShape, Inc., 1575 Northside Drive, NW, Suite 440, Atlanta, GA 30318, USA
| | - W Allen Chang
- Vertera, Inc., 311 Ferst Drive NW Suite L1328, Atlanta, GA 30332, USA
| | - Annie E Macedo
- Wallace H. Coulter Department of Biomedical Engineering, 313 Ferst Drive, Georgia Institute of Technology and Emory University, Atlanta, GA 30332, USA
| | - Angela S P Lin
- George W. Woodruff School of Mechanical Engineering, 801 Ferst Drive, Georgia Institute of Technology, Atlanta, GA 30332, USA; Parker H. Petit Institute for Bioengineering and Bioscience, 315 Ferst Drive, Georgia Institute of Technology, Atlanta, GA 30332, USA
| | - Jennifer M Boothby
- Wallace H. Coulter Department of Biomedical Engineering, 313 Ferst Drive, Georgia Institute of Technology and Emory University, Atlanta, GA 30332, USA
| | - Daniel C Whittingslow
- Wallace H. Coulter Department of Biomedical Engineering, 313 Ferst Drive, Georgia Institute of Technology and Emory University, Atlanta, GA 30332, USA
| | - Robert A Carson
- George W. Woodruff School of Mechanical Engineering, 801 Ferst Drive, Georgia Institute of Technology, Atlanta, GA 30332, USA
| | - Robert E Guldberg
- George W. Woodruff School of Mechanical Engineering, 801 Ferst Drive, Georgia Institute of Technology, Atlanta, GA 30332, USA; Parker H. Petit Institute for Bioengineering and Bioscience, 315 Ferst Drive, Georgia Institute of Technology, Atlanta, GA 30332, USA
| | - Ken Gall
- School of Materials Science and Engineering, 771 Ferst Drive, J. Erskine Love Building, Georgia Institute of Technology, Atlanta, GA 30332, USA; George W. Woodruff School of Mechanical Engineering, 801 Ferst Drive, Georgia Institute of Technology, Atlanta, GA 30332, USA; Parker H. Petit Institute for Bioengineering and Bioscience, 315 Ferst Drive, Georgia Institute of Technology, Atlanta, GA 30332, USA
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Hoyt AJ, Yakacki CM, Fertig RS, Dana Carpenter R, Frick CP. Monotonic and cyclic loading behavior of porous scaffolds made from poly(para-phenylene) for orthopedic applications. J Mech Behav Biomed Mater 2014; 41:136-48. [PMID: 25460410 DOI: 10.1016/j.jmbbm.2014.10.004] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2014] [Revised: 10/02/2014] [Accepted: 10/06/2014] [Indexed: 11/19/2022]
Abstract
Porous poly(para-phenylene) (PPP) scaffolds have tremendous potential as an orthopedic biomaterial; however, the underlying mechanisms controlling the monotonic and cyclic behavior are poorly understood. The purpose of this study was to develop a method to integrate micro-computed tomography (μCT), finite-element analysis (FEA), and experimental results to uncover the relationships between the porous structure and mechanical behavior. The μCT images were taken from porous PPP scaffolds with a porosity of 75vol% and pore size distribution between 420 and 500µm. Representative sections of the image were segmented and converted into finite-element meshes. It was shown through FEA that localized stresses within the microstructure were approximately 100 times higher than the applied global stress during the linear loading regime. Experimental analysis revealed the S-N fatigue curves for fully dense and porous PPP samples were parallel on log-log plots, with the endurance limit for porous samples in tension being approximately 100 times lower than their solid PPP counterparts (0.3-35MPa) due to the extreme stress concentrations caused by the porous microarchitecture. The endurance limit for porous samples in compression was much higher than in tension (1.60MPa). Through optical, laser-scanning, and scanning-electron microscopy it was found that porous tensile samples failed under Mode I fracture in both monotonic and cyclic loading. By comparison, porous compressive samples failed via strut buckling/pore collapse monotonically and by shearing fracture during cyclic loading. Monotonic loading showed that deformation behavior was strongly correlated with pore volume fraction, matching foam theory well; however, fatigue behavior was much more sensitive to local stresses believed to cause crack nucleation.
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Affiliation(s)
- Anthony J Hoyt
- University of Wyoming, Department of Mechanical Engineering, Laramie, WY, USA
| | - Christopher M Yakacki
- University of Colorado Denver, Department of Mechanical Engineering, Denver, CO, USA
| | - Ray S Fertig
- University of Wyoming, Department of Mechanical Engineering, Laramie, WY, USA
| | - R Dana Carpenter
- University of Colorado Denver, Department of Mechanical Engineering, Denver, CO, USA
| | - Carl P Frick
- University of Wyoming, Department of Mechanical Engineering, Laramie, WY, USA.
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